One component of a drill stem includes a sonde housing. Sonde units are used to provide feedback information for devices such as directional drills. A sonde unit typically transmits information such as depth, lateral distance, “clock” rotation about a drilling axis, etc. The information is used for applications such as steering a directional drill.
In a directional drilling operation, the sonde unit is typically housed at the tip of the drill stem, just behind the steering blade. Ground drilling requires large amounts of forward linear force, as well as large amounts of torque as applied to the drill stem. The housing for the sonde unit therefore requires a robust design that can withstand the forces needed for the drilling operation. In addition to the requirements of the drilling operation, the sonde unit contains sensitive circuitry and components that require careful handling.
Sonde housing designs have included both front loading and side loading configurations. Side loading configurations include a cylinder shaped housing with a diameter that is substantially the same as a drill stem diameter, with an opening cut into the side of the cylinder for insertion of the sonde. A cover is secured over the opening with screws or bolts to enclose the sonde during the drilling operation. The side opening design, however, does not provide the same level of strength in response to torque as compared to a cylinder without an opening cut into the side.
Front loading sonde housing designs do not have sonde insertion openings cut into the side. The sonde is inserted into an opening in the front of the cylindrical housing, and a threaded cap is secured over the front opening by threading the cap into the periphery of the cylinder. In this way, current front loading sonde housings enclose the sonde during the drilling operation. However, the threaded cap is difficult to remove after the drilling operation is complete due to tightening of the threads during rotation of the drill stem in a drilling operation. Large tools such as a pipe wrench are frequently needed to remove the threaded cap. Pipe wrenches or similar methods requiring large forces are inconvenient, and may be dangerous to the operator.
In addition to sonde housings, other drill stem components such as steering blade holders, sections of drill rod, etc. are selectively coupled together in a drill stem. Several combinations of these components are coupled together in the drill stem using configurations and methods that also exhibit the problems described above.
What is needed is a drill stem component connection system and method that provides structural integrity for drilling operations, while providing ease of assembly and disassembly.